Piston-ring casting



Dec. 2, 1930. T. E. MCFALL; 1,783,886

7 1930 2 "sheets-sneak -1 Dec; 2, 1930. MCFALL Y 1,783,886

PISTON RING CASTING Filed Feb. 17, 1950 {sheets-shew 2 no QTL COTPatented Dec. 2, 1930 UNITED STATES manow n MCFALL, or SPARTA, :uncrmmnms'rolv-nme casrme Application filed Februaryil'i, 1980. Serial No.429,001.

This invention relates to piston rings, being more particularlyconcerned with a novel construction of piston ring casting.

I have heretofore made application for a patent on a process'of pistonring casting which was filed March 5, 1929, Ser. N 0. 344,37 3. My priorinventionwas directed to the making of a piston ring casting of a widthsuch that when it was cut or split midway between its oppositeparallel-flat sides two ring castings were produced from each of which apiston ring was readily made, both rings being of uniform characterthroughout and the defects, waste and the like coming from individuallycasting ring castings of the very narrow widths of rings now usedthereby avoided, with an exceptional advantage from the standpoint ofeconomy, and with a further advantage of elimination of combined carbonand iron hard spots either in the body or adjacent the surface of thering casting, prevalent where the rings of narrow width are individuallycast, and which serve to destroy machining tools and at the same timedestroy the usefulness of the rings for internal combustion enginepurposes.

The present invention is a further step in perfecting the invention Ihave previously made, above identified. Ring castings, as now almostuniversally made, are of an outof-round character. The patterns for thering castings, first of circular form, are parted at one side andsegments or gap pieces, so called, inserted between the two ends of eachof the ring patterns at the partings thereby v distorting the patternsto an out-of-round condition. The ring castings made from a pattern ofthis type are accordingly out-ofround to the extent produced by theinsertion by the segment or gap piece. In finishing the rings for use ininternal combustion engines the castings have a part cut therefromdirectly at said inserted segment of the pattern, reproduced in thecasting; so that when the segment has been removed the ring casting mayhave its ends brought together and assume a perfectly circular form. Itis of course to be understood throughout that the usual allowances forshrinkage of metal in cooling and for the machining operations requiredare made in producing the pattern for the ring casting.

My invention is directed to an exceedingly practical yet-very simpleimprovement on the double ring castings whereby when the same are sawedor otherwise split midway between their fiat sides, the two ringcastings produced will be both marked at the proper places where thesegment is to be removed. A further object of the invention is toprovide the ring castings with this mark and make use thereof inmaintaining a double ring casting against movement on the arbor whichholds them during the sawing operation whereby a double ring casting issplit midway between its parallel flat sides to produce two ringcastings.

An understanding of theinvention may be had from the followingdescription taken in connection with the accompanying drawings, inwhich,

Fig. 1 is a partial vertical section and elevation showing the manner inwhich the ring castings may be split.

Fig. 2 is a partial plan and horizontal sectional view of the structureshown in Fig. 1.

Fig. 3 is a perspective view of the double ring casting of my invention.

Fig. 4 illustrates the same split midway between its parallel upper andlower sides, and indicates the segments removed therefrom to form thepartings or gaps in the piston rings, and

, Figs. 5 and 6 are perspective views, similar to Fig. 3, illustratingother forms in which the invention may be embodied.

Like reference characters refer to like parts in the different figuresof the drawing.

The ring casting indicated at 1 in Fig. 3 is a casting which, when splitmidway between its upper and lower flat sides, provides two ringcastings from each of which a piston ring may be made. In the preferredform of my invention at the inner side of the ring casting 1 a verticalgroove 2 is made which extends the full distance between the upper andlower sides of the casting.

This groove marks the place where the gap I piece or segment is to becut from the ring casting and is ordinarily disposed directly at thegate where the molten metal passes into the ring shaped mold to make thecasting. With a groove, such as indicated at 2, in the double ringcasting thus made, when the casting is split midway between its sides itforms two rings 3 as shown in Fig. 4:. In Fig. 4 there is also anindication of the segments or gap pieces as having been cut away andremoved, the parts which are cut away being shown in dotted lines, andit is evident that both of the ring castings 3, formed by splitting asingle ring casting 1, are marked at their inner sides with one-half ofthe groove 2, each half of the groove being shown in dotted lines inFig. 4 at 2a.

Accordingly with my invention and with the marking grooves 2a at theplaces where the segments or gap pieces in the castings are to beremoved, the ring castings 3 continue to be marked after they have beenproduced by splitting a double ring casting 1 and there is no danger ofany loss of good ring castings from an inability to know where to removethe segment or gap pieces for the ring parting. It is further evidentthat in the matter of casting the ring castings 1, the groove is formedwhen the ring casting is molded and cast, it being evident that thepattern may be drawn upwardly from the sand, the pattern being groovedat its inner side similar to that in the casting at 2 which does notinterfere with the sand of the mold,

when the pattern is drawn.

This form of ring casting has another very desirable utilitarianfeature. In the splitting of the double ring castings ito two parts itis designed that they shall be placed around an expanding arborstructure and held thereon while the splitting of the double ringcastings 1 is performed by a gang saw assembly. The arbor includes alongitudinal shaft 5 on which, at spaced apart points, enlarged conesections 6 are provided. Around the central shaft are a plurality ofseparated expanding arbor members 7 lying parallel to the shaft 5 andformed at their inner sides with inwardly extending projections 8 havingcooperating conical surfaces to bear against the conical part 6 of theshaft 5 (see Fig. 2). The outer sides of the expanding arbor members 7present surfaces substantially sectors of a cylinder on which aplurality of ring casting receiving grooves are made between outwardlyextending flanges 9; and at the bottom of the grooves are slots 10 thepurpose of-which will hereafter appear. The ring castings 1 may beplaced over the expanding arbor members 7 when the arbor is collapsedand adjusted to the grooves between the flanges 9 and then, by expandingthe arbor by a lengthwise movement of the shaft 5 or an equivalentlengthwise movement of the members 7, the rings are received in thegrooves of the arbor members 7 and properly positioned for the action ofthe cutting saws thereon.

Metal saws acting upon the rings are liable to encounter someresistance'and the friction is considerable, so that it is verydesirable to hold the ring castings against any movement about theexpanding arbor. To this end a flat metal plate 11 is connected to thearbor members 7 at a side thereof, as shown in Figs. 1 and 2, andprojects a short-distance beyond the bottoms of the groove in saidsection, the distance which it projects being substantially equal to thedepth of the groove 2 in a r1 ng casting 1. Therefore by locating thering castings so that the grooves 2 are positioned at the outer edge ofthe plate 11, said plate enters the groovesand upon the expansion of thearbor the ring castings are held positively against any turning movementaround the arbor. The outer edge of the plate 11 is formed with aplurality of spaced apart slots 12 which come into' conjunction with thegrooves 10 in the arbor member 7 to which it is attached.

The ring castings, after being placed upon the arbor and the arborexpanded, are s lit midway between their flat sides prefera ly by thegang saw construction wherein a plurality of metal saws 13 are locatedaround a shaft 14 and spaced from each other by collars 15 around theshaft. In practice these collars 15 may extend out further than shown inthe drawing, or so that when the saws pass through the ring castings theouter curved surface of the collars will be spaced only a very shortdistance from the outer curved surfaces of the castings. The grooves 10and 12 in the arbor members 7 and in the plate 11 respectively are forthe purpose of permitting the saws to pass completely through the ringcastings 1 and divide the same without sawing into the arbor 7 and theplate 11.

It is therefore evident that a double ring casting such as indicated at1 formed with a groove at its inner side like that indicated at 2 is ofgreat value in the practical production and machining operationsrequired to divide a double ring casting into two practical piston ringcastings of narrow width.

Fig. 5 shows a slight modification of the structure from that shown inFig. 3 in that the groove at 2 does not extend entirely to the upperside of the double ring casting 1. The groove 16 there shown extendsfrom the lower side of the ring casting more than onehalf the distanceto the upper side so that when the casting is divided on the dottedlines indicated at 17 both ring castings produced will still have anindicating mark thereon to tell where the segment or gap piece should becut away. The invention accordingly is in no sense limited to themarking groove at the inner side of the ring extending the full distancebetween the opposite flat sides of the ring; but it is only that bothhalves 3 of the double ring casting a groove appearing at both sides ofthe split- 1 still carry a pro er mark for guidance in ting plane.

the further manu acturing process.

In Fig. 6 instead of a groove 2 there is shown a projection 18 whichalso may extend either the full height of the ringor only a part of theheight of the same as the slot 16 does in Fig. 5; and it is alsoapparent that whether the marking device be on the.

inner or on the outer side of. the ring it is also comprehended by myinvention. In fact the invention is not to be restricted to specificstructural details disclosed but is to be comprehensive of all formscoming within the scopeof the claims appended hereto which define theinvention.

I claim:

l. A piston ring casting adapted to be split betwem its opposed parallelsides into two ring castings, said piston ring casting at a side thereofhaving a marking means extending from one side of the casting across theplane in which the casting is split to make two ring castings, for thepurposes described.

2. piston ring casting adapted to be split substantially midway betweenits opposed flat sides to make two ring castings, and a marking means onsaid ring casting at each side of a central plane located substantiallymidway between the opposite flat sides of the ring casting, whereby whenthe ring casting is split into two parts each part thereof will carry amarking indication, for the purposes described.

3. A piston ring casting having a groove at one point at its inner side,said groove extending from one flat side of-the ring casting to theother parallel fiat side thereof.

4. A piston ring casting having a transverse groove at a point at itsinner side extending from thelower flat side of the casting to andacross a plane midwaybetween the upper and lower flat sides of the ringcasting. I

5. A piston ring casting having a groove at one point at a curved sidethereof, said groove extending from one flat side of the ring casting tothe other parallel flat side thereof.

6. A piston ring casting adapted to be split, between its oppositeparallel sides into two ring castings, said piston ring casting havingmarking means appearing at both sides of the splitting plane and saidmarking means extending into a diiferent plane than the surface on whichit is located.

7. A piston ring casting adapted to be split between its oppositeparallel sides into two ring castings, said piston r-ing casting havinga rib appearing at both sides of the splitting, plane. I

8. A piston ring casting adapted to be split between its oppositeparallel sides into two In testimony whereof I aflix my signature.

THURLOW E. MCFALL.

necessary that it shall extend far enough ring castings, said pistonring casting having

